Aircraft engine pre-dressing unit for testing facility

ABSTRACT

A turbofan text cell pre-dressing unit that enables the installation of the engine in a text cell in minimal time is provided.

TECHNICAL FIELD

The invention relates to a gas turbine engine pre-dressing unit for anaircraft gas turbine engine testing facility.

BACKGROUND OF THE ART

Aircraft gas turbine engines are normally subjected to at least one“pass-off” operational text, after production and before they areshipped, to ensure proper operation of each engine. The pass-off test istypically conducted within a test cell with the engine heavilyinstrumented to measure and record relevant parameters. Accordingly,each engine must be prepared or “dressed” with the necessary testequipment, such as accessories (e.g. starter motor), instruments (e.g.sensors) and services (e.g. fuel, oil supplies) that are required forthe testing and operation of the engine within the test cell. Once thepass-off test is completed, the engine must then be “undressed” beforeit is packaged and shipped.

Dressing the engine is a time-consuming and a labor-intensive activity,due to the sheer magnitude of instruments used in testing and thesensitivity of those instruments to shock and mishandling. An operatorlocates, assembles and connects to the engine the specific testequipment, such as accessories, instruments and services that arerequired for testing the particular model of engine. This process is asignificant source of downtime for the test cell and requires asignificant amount of material handling and storage. It is also prone tooperator error. Improvement is needed.

SUMMARY

According to one broad aspect, there is provided a pre-dressing unit foran aircraft turbofan engine testing, the pre-dressing unit comprising: asupport frame including an engine mount; an intake duct supported by thesupport frame and configured to mount to an intake end of the turbofanengine; an exhaust duct supported by the support frame and configured tomount to an exhaust end of the turbofan engine; an engine-side dataconnector mounted to the support frame and having a functional datainterface comprising a plurality of engine-side data connections; andequipment associated with the operation and testing of the engine, saidequipment including test instruments mounted to the exhaust duct andfunctionally connected to a corresponding engine-side connection on theengine-side data connector for data communication therewith.

According to another aspect, there is provided a pre-dressing unit foran aircraft gas turbine engine testing, the pre-dressing unitcomprising: a support frame; an intake duct supported by the supportframe for coupling to an intake end of the gas turbine engine; anexhaust duct supported by the support frame for coupling to an exhaustend of the gas turbine engine; an engine-side connector structurallyattached to the support frame and connected for data communication withtest equipment associated with the operation and testing of the engine,the engine side-connector having a connecting interface including bothdata connectors and structural connectors configured to be interfacedall at once in a single operation with corresponding data connectors andstructural connectors of a test cell structure.

According to a further aspect, there is provided a connector assemblyfor a turbofan engine testing facility, the connector assemblycomprising: an engine-side connector structurally attached to the gasturbine engine, having a functional interface comprising a plurality ofengine-side connections functionally connected to equipment associatedwith the operation and testing of the engine; and a mating test-sideconnector associated with the testing facility comprising a plurality ofcorresponding test-side connections; the engine-side connector and thetest-side connector having cooperating guiding mechanism configured tostructurally co-operate and restricting relative motion between theengine-side connector and the test-side connector along an engagementaxis while establishing alignment of the engine-side connections withthe test-side connections as the engine-side connector and the test-sideconnector are brought together for connection; and the engine-sideconnector and the test-side connector having a cooperating lockingmechanism to releasably lock the engine-side connector to the test-sideconnector along the engagement axis.

According to a still further general aspect, there is provided apre-dressing unit for an aircraft turbofan engine testing, thepre-dressing unit comprising; a support frame including an engine mount;an intake duct supported by the support frame and configured to mount toan intake end of the turbofan engine; an exhaust duct supported by thesupport frame and configured to mount to an exhaust end of the turbofanengine; an engine-side data connector mounted to the support frame andhaving a functional data interface comprising a plurality of engine-sidedata connections; and equipment associated with the operation andtesting of the engine, said equipment including an engine oil pressureregulator carried by the support frame and functionally connected to acorresponding engine-side connection on the engine-side data connectorfor allowing adjustment of oil pressure during engine testing operationwithout having to stop the engine.

DESCRIPTION OF THE DRAWINGS

Reference is now made to the accompanying Figures, in which:

FIG. 1 is a schematic axial cross-section view of a gas turbine engine.

FIG. 2 is an isometric view showing a front side of a gas turbine enginepre-dressing unit.

FIG. 3 is an isometric view showing a gas turbine engine beingtransferred from a production stand to a gas turbine engine pre-dressingunit.

FIG. 4 is an isometric view showing the front side of the pre-dressingunit of FIG. 2 with a gas turbine engine mounted thereon.

FIG. 5 is an isometric view showing a back side of the pre-dressing unitof FIG. 2 with a gas turbine engine mounted thereon.

FIG. 6 is an enlarged isometric view of front engine mounts.

FIG. 7 is an enlarged isometric view of a rear engine mount.

FIG. 8 is an isometric view of a base of the pre-dressing unit of FIG.2.

FIG. 9 is an isometric view of a support frame and engine-side connectorof the pre-dressing unit of FIG. 2.

FIG. 10 is an isometric view of a test-side connector.

FIG. 11 is a front view of the test-side connector of FIG. 10.

FIG. 12 is a cross-sectional view of the connector of FIG. 10 along lineA-A of FIG. 10 wherein a keeper is in an unlocked position.

FIG. 13 is a cross-sectional view of the connector of FIG. 10 along lineA-A of FIG. 10 wherein the keeper is in a locked position.

FIGS. 14A to 14D are horizontal cross-sectional views of the test-sideconnector of FIG. 10 together with the engine-side connector of FIG. 9,showing the sequential steps of connecting the engine-side connector andthe test-side connector together.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a turbo-fan engine 10 of a type preferably providedfor use in subsonic flight, generally comprising in serial flowcommunication a fan 12 through which ambient air is propelled, amultistage compressor 14 for pressurizing the air, a combustor 16 inwhich the compressed air is mixed with fuel and ignited for generatingan annular stream of hot combustion gases, and a turbine section 18 forextracting energy from the combustion gases. It will be understoodhowever that the invention is equally applicable to other types of gasturbine engines, such as a turbo-shaft, a turbo-prop, or auxiliary powerunits.

FIG. 2 shows an aircraft gas turbine pre-dressing unit (in this case,configured for a turbofan engine), shown generally at 20, that can beused to prepare engine 10 for a pass-off test within a test cell (notshown). As will be seen hereinafter, the pre-dressing unit 20 ispreferably adapted to be all-inclusive such that it comprises preferablyall the test equipment, such as accessories, instruments and services(described further below) that are required for pre-dressing the engine10 prior to testing in the test cell. The mobility of the unit 20 allowsthe pre-dressing to be readily done outside of the test-cell, i.e. whilethe test cell is in use, thus reducing test cell downtime.

The pre-dressing unit 20 comprises a support frame 30 (FIG. 9) that isremovably mounted on a mobile base 50 (FIG. 8). The support frame 30comprises a central support member 34 at an upper end of which ahorizontal rail 33 is affixed. An instrumented intake duct 31 and aninstrumented exhaust duct 32 are permanently mounted, via respectivesupport members 42, to separate sleeves 35 which are independentlyslidably supported on the rail 33 in a substantially axial alignment.The sleeves 35 allow for the intake duct 31 and the exhaust duct 32 tobe moved axially along the rail 33 either towards or away from eachother. A locking mechanism (not shown) can be provided to releasablylock the sleeves 35 in place along the rail 33. The pre-dressing unit 20also comprises preferably all the test equipment required for operatingand testing the engine 10. The intake and exhaust ducts 31 and 32 arepreferably instrumented with probes and sensors to obtain intake andexhaust temperature and pressure feedback while the engine 10 is beingtested. The intake duct 31 is also typically equipped with an intakeguard 38 (see FIG. 3). The test equipment mounted to unit 20 alsoincludes an engine oil pressure regulator 39 (described further below),a starter 40, an automatic oil filing system 41 and fuel supply line(not shown). The pre-dressing unit 20 may further include various othertest equipment (not shown) predisposed on or mounted to unit 20, such asengine temperature and pressure sensors and other equipment foroperation, testing and evaluation of gas turbine engines.

FIG. 3 shows an operator 21 in the process of transferring the engine 10from a build stand 22, on which the engine 10 is assembled within theproduction facility, to the pre-dressing unit 20. The operator 21transfers the engine 10 from the build stand 22 to the pre-dressing unit20 and then prepare or dress the engine 10 on the pre-dressing unit 20before transporting it to the test cell using a floor transport system23 engageable with mobile base 50.

FIGS. 4 and 5 show the pre-dressing unit 20 on which the engine 10 hasbeen mounted. During installation of the engine 10 on the pre-dressingunit 20, the intake duct 31 and exhaust duct 32 are moved apart fromeach other so as to allow the engine 10 to be inserted between them. Theengine 10 is first secured to the support frame 30 via two front enginemounts shown generally at 43 in FIG. 6 and a rear engine mount showngenerally at 44 in FIG. 7. The front engine mounts 43 each comprise afront bracket 45 affixed to the support frame 30, on which a holder 47is secured. The holder 47 comprises an aperture (not shown) forreceiving a locking pin (not shown) that interlocks a front enginebracket 13 secured to the engine 10 to the holder 47. The rear enginemount 44 comprises a rear bracket 48 that is affixed to the supportframe 30 and a link 49 that is secured to the rear bracket 48. The link49 is then secured to the engine.

Once the engine 10 has been mounted to the support frame 30, the intakeduct 31 and exhaust duct 32 ar then moved towards each other and coupledto the intake and exhaust ends of the engine 10 respectively. The intakeduct 31 is coupled to the engine 10 via an intake duct flange 36 and theexhaust duct 32 is coupled to the engine via an exhaust duct flange 37.

Once the intake duct 31 and the exhaust duct 32 have been coupled to theengine 10, the test equipment mounted to the unit 20, including theengine oil pressure regulator 39, and the starter 40, the automatic oilfilling system 41 and the fuel supply line (not shown) are connected tothe engine 10.

As mentioned hereinabove, the intake duct 31 and exhaust duct 32 arealso pre-instrumented so that only connections to the engine 10 must bemade. This further increase the efficiency of the pre-dressing process.Consequently, the engine 10 can be pre-dressed and made ready fortesting in a very short period of time and typically have a pre-dresstime of less than 35 minutes and test cell installation time of lessthan 5 minutes.

The base 50 of the pre-dressing unit 20 is shown in FIG. 8 and comprisesmany features that facilitate the task of pre-dressing the engine 10 andalso has a relatively small footprint which requires a minimal amount offloor space. The base 50 comprises floor pads 51 for resting thepre-dressing unit 20 on a floor but also has brackets 55 that facilitatethe transport of the pre-dressing unit 20 using floor transport system23. The base 50 also comprises a handle 53 and a supporting post 54 onwhich the supporting frame 30 can be removably mounted. The base 50further comprises a shelf 56 and storage boxes 52 for storing fasteners,spare components, sensors or the like.

As seen in FIGS. 5 and 9, the support frame 30 comprises an engine-sideconnector generally shown at 60. The engine-side connector 60 preferablyprovides a unitary functional interface for all test equipmentassociated with the engine 10. For example, the engine-side connector 60provides a functional interface to the oil filling system 41 and thefuel supply line, and, electrical connections to the engine oil pressureregulator 39, the starter 40 and other sensors or instruments requiredfor the operation and testing of the engine 10. This allows theengine-side connector 60 to be connected to a corresponding test-sideconnector generally shown at 80 in FIG. 10, within the test-cell andtransfer the operation of all the test equipment associated with theengine 10 to the test cell into one single connector. The combination ofthe engine-side connector 60 and the test-side connector 80 is referredbelow as a connector assembly.

In reference to FIG. 9, the engine-side connector 60 comprises anengine-side connector face 61, a plurality of engine-side connections 62that are disposed within the engine-side connector face 61, two lugs 63projecting from the engine-side connector face 61, a pair of guidingmembers 65 disposed at opposite sides of the engine-side connector face61 and a locking bracket 66. Each lug 63 has a roller 64 attached at adistal end thereof and functions as a follower.

In reference to FIGS. 10-13, the test-side connector 80 comprises atest-side connector face 81 on which a plurality of test-sideconnections 82 are disposed. The test-side connector face 81 alsocomprises two apertures 94, a latch 86 and a pair of guiding passages 85disposed at opposite sides of the test-side connector face 81. Thepassage 85 are defined by a passage opening 93, front rollers 90 andrear rollers 91. One of the passages 85 also comprises an inwardlytapered portion 92. The spacing between the front rollers 90 is greaterthan the spacing between the rear rollers 91.

As shown in FIGS. 12 and 13, the test-side connector 80 furthercomprises two receiving apertures 97 and a movable keeper 83 disposedbehind the test-side connector face 81 that is linearly movable betweenan unlocked and a locked position. The keeper 83 is actuated by a linearactuator 100 (FIG. 13) which may be a pneumatic or hydraulic cylinder, ascrew drive or the like. FIG. 12 shows the keeper 83, in the unlockedposition and FIG. 13 shows the keeper 83 in the locked position. Thekeeper 83 has two channels 84, each having a channel opening 87, a firstchannel portion 88 and a second channel portion 89. The first channelportion 88 has a tangential vector 95 that is at an angle from anengagement axis 96 of the test-side connector 80.

When the keeper 83 is in the unlocked position, the channel openings 87are aligned with the apertures 94 and when the keeper 83 is in thelocked position, the channel openings 87 are laterally offset relativeto the apertures 94.

Once the engine 10 has been pre-dressed on the pre-dressing unit 20, thepre-dressing unit 20 is transported to the test cell. The support frame30 together with the pre-dressed engine 10 and the base 50 and theengine-side connector 60 is then connected to the correspondingtest-cell connector 80 within the test cell. The base 50 is disengagedfrom the support frame 30 by lowering the test cell lift platform. Asthe base 50 connecting shaft 54 disengage from support frame 30, thesafety redundant latch 86 shown in FIG. 10 also becomes engaged to thelocking bracket 66 shown in FIG. 9 and thereby positively locks theengine-side connector 60 and the test-side connector 80 together. Thebase 50 is removed from test cell prior engine testing.

The engine-side connector 60 is structurally attached to the supportframe 30 so that in addition to providing a functional interface to thetest equipment of the pre-dressing unit 20, the engine-side connector 60also allows the engine 10 and the support frame 30 to be physicallysupported within the test cell during the pass-off test. Thus, theengine-side connector 60 and the test-side connector 80 provide acomplete unitary interface between the test cell and the gas turbineengine 10 and allow the engine to be functionally and physicallyconnected to the test cell all at once in a single sequence.

In order to ensure proper connection of the plurality of engine-sideconnections 62 on the engine-side connector 60 to the correspondingtest-side connections 82 on the test-side connector 80, the connectorassembly is provided with a cooperating guiding mechanism which isdescribed in more details below.

Further, the engine-side connector 60 must also be securely connected tothe test-side connector 80 during testing in order to physically supportthe engine 10 and simultaneously maintain functional connections betweenthe test cell and the test equipment. The connector assembly must beable to withstand the forces that result from the thrust produced by theengine 10 during testing. Accordingly, the connector assembly is alsoprovided with a cooperating locking mechanism which prevents thedisconnection of the engine-side connector 60 and the test-sideconnector 80 once they have been connected.

The guiding mechanism and the locking mechanism will be described inreference to FIGS. 14A-14D. FIGS. 14A-14D show the engine-side connector60 and the test-side connector 80 at various stages of engagementleading to their secure connection.

In FIG. 14A, the connector assembly is at an initial stage of engagementwherein the guiding members 65 of the engine-side connector 60 haveentered their corresponding passages 85 in the test-side connector 80and have passed the front rollers 90. At this stage, coarse alignment ofthe engine-side connections 62 and test-side connections 82 isestablished. As the guiding members 65 proceed further into the passages85 and come in contact with the rear rollers 91, finer alignment isachieved. The space between the rear rollers 91 is less than that of thefront rollers 90 and therefore the width of the passage 85 is reduced atthe rear of the passage 85. The guide members 65 and the correspondingpassage 85 essentially restrict the relative motion between theengine-side connector 60 and the test-side connector 80 along anengagement axis 96.

In FIG. 14B, the engine-side connector 60 and the test-side connector 80are closer together. At this stage the guiding members 65 have passedthe rear rollers 91 and the engine-side connections 62 are insubstantial alignment with the test-side connections 82 and aretherefore ready to be connected together. At this stage of engagement,the rollers 64 on the lugs 63 have also passed through theircorresponding apertures 94 in the test-side connector face 81 and haveentered the channels 84 in the keeper 83 via the channel openings 87.The keeper 83 is shown in the unlocked position wherein the channelopenings 87 are aligned with their corresponding apertures 94.

The next step is shown in FIG. 14C where the keeper 83 is moved towardsthe locked position by the linear actuator 100. The rollers 64 areengaged by the first channel portions 88 which have a tangential vector95 at an angle from the engagement axis 96. The movement of the keeper83 induces a camming action on the rollers 64 which causes the rollers64 to be pulled inward along the engagement axis 96 and thereby causesthe engine-side connector 60 and the test-side connector 80 to becomeconnected together. Accordingly, any connection forces that may beneeded to functionally connect the engine-side connections 62 to thetest-side connections 82 is exerted by the actuator 100 through thekeeper 83 and not by the operator 21. This ensures a consistentconnection between the engine-side connector 60 and the test-sideconnector 80 which is not dependent on operator judgment or physicalstrength.

Also, as the engine-side connector 60 and the test-side connector 80become connected together, the distal ends of the guiding member 65enter the receiving aperture 97 of the test-side connector 80, and, theoutwardly tapered portion 67 on the opposite guiding member 65 becomesin contact with the corresponding inwardly tapered portion 92 in thepassage 85. This produces a firm fit between the engine-side connector60 and the test-side connector 80. The final step is shown in FIG. 14Dand involves further movement of the keeper 83 towards the lockedposition. This second channel portion 89 of the channel 84 is orientedin a direction that is perpendicular to the engagement axis 96 andtherefore no camming action on the roller 64 is induced at this stage.This final sequence engages the nose pin 101 into the guide member hole65A and the cylinder shaft 102 into the guide member hole 65B tocomplete the engagement.

At the completion of the engine pass-off test, the base 50 is engagedinto the support frame 30 by raising the lift platform, this action alsodisengage the redundant safety latch 86. Then, the keeper 83 is movedtowards the unlocked position by the linear actuator 100 whereby thenose pin 101 and cylinder shaft 102 exit the guide members holes 65A and65B and the rollers 64 becomes once again engaged by the first channelportions 88 of the channel 84. The movement of the keeper 83 induces acamming action on the rollers 64 which causes the rollers 64 to bepushed outward along the engagement axis 96 and thereby causes theengine-side connector 60 and the test-side connector 80 to becomedisconnected from each other. Accordingly, the force that may be neededto functionally disconnect the engine-side connections 62 from thetest-side connections 82 is exerted by the actuator 100 through thekeeper 83 and not by the operator 21. The engine-side connector 60 andthe test-side connector 80 can then be freely separated from each otheralong the engagement axis 96 until the guide members 65 exit thepassages 85.

Once the engine-side connector 60 and the test-side connector 80 aredisconnected and upon a successful completion of the pass-off test, thepre-dressing unit 20 is transported to a shipping and packaging area ofthe production facility where the engine is undressed, packaged andshipped to the customer.

The locking mechanism shown in this embodiment comprises a keeper 83 andchannel configuration adapted for linear motion of the keeper 83,however, one of ordinary skill in the art would appreciate that otherconfigurations are also possible. The proposed keeper is a compactsystem which pulls with tandem pullers to insure parallel movementagainst uneven reaction force of connector friction and springresistance. It is a double function system, pulling/pushing andadditional massive locks in the same sequence. Alternatively, a ratchetmechanism could also be used to progressively lock the connectorassembly as the engine-side connector 60 and the test-side connector 80are brought together.

Referring again to FIG. 2, the engine oil pressure regulator 39 ispreferably an electric motor (not shown) having a suitable controlsystem (not shown) which communicates with the motor through the datainterface of connectors 60-80. The engine oil pressure regulator 39allows test cell operators to adjust the oil pressure “on the fly”during engine operation in the test cell, without having to stop theengine and make the changes manually. The above description is meant tobe exemplary only, and one skilled in the art will recognize thatchanges may be made to the embodiments described without departing fromthe scope of the invention disclosed. Although the above descriptionrelates to a pre-dressing unit 20 having a side-mounted engine-sideconnector 60, the pre-dressing unit 20 could be adapted to have atop-mounted engine-side connector. The pre-dressing unit could also beadapted to be transported using an overhead (or other) trolley transportsystem instead of a mobile base. It is also apparent that thepre-dressing unit described above can be fabricated using any suitabletechniques, including conventional manufacturing procedures using asuitable material(s) such as a structural grade steel or anycombinations of suitable materials. It will also be understood that theapparatus is modifiable to apply to other types of g as turbine engines,such as a turboshaft, a turboprop, and auxiliary power units. Stillother modifications which fall within the scope of the present inventionwill be apparent to those skilled in the art, in light of a review ofthis disclosure, and such modifications are intended to fall within theappended claims.

1. A pre-dressing unit for an aircraft turbofan engine testing, thepre-dressing unit comprising: a support frame including an engine mount;an intake duct supported by the support frame and configured to mount toan intake end of the turbofan engine; an exhaust duct supported by thesupport frame and configured to mount to an exhaust end of the turbofanengine; an engine-side data connector mounted to the support frame andhaving a functional data interface comprising a plurality of engine-sidedata connections; and equipment associated with the operation andtesting of the engine, said equipment including test instruments mountedto the exhaust duct and functionality connected to a correspondingengine-side connection on the engine-side data connector for datacommunication therewith.
 2. A pre-dressing unit according to claim 1,wherein the support frame is removably mounted to a base, and whereinthe engine mount is provided on one side of the support frame to permitside-mounting of the turbofan engine to the support frame.
 3. Apre-dressing unit according to claim 2, wherein the base includes anupstanding support post, and wherein the support frame is removablymounted to an upper end of said support post.
 4. A pre-dressing unitaccording to claim 1, wherein the intake duct and exhaust duct aremovable towards and away from each other.
 5. A pre-dressing unitaccording to claim 4, wherein the support frame comprises a horizontalrail, and wherein at least one of said intake and exhaust ducts isslidably mounted to said horizontal rail.
 6. A pre-dressing unitaccording to claim 1, wherein the engine-side data connector isstructurally attached to the support frame and is provided withstructural connections to physically support the engine within thetesting facility when the engine-side data connector is connected to acorresponding test-side connector associated with the testing facility.7. A pre-dressing unit according to claim 1, wherein the equipment areselected from the group consisting of: a starter motor, an engine oilpressure regulator, a pressure sensor, a temperature sensor, a fuelsupply line and an oil supply line.
 8. A pre-dressing unit according toclaim 1, wherein the intake duct and the exhaust duct are supported by arail fixedly mounted to said engine-side data connector.
 9. Apre-dressing unit for an aircraft gas turbine engine testing, thepre-dressing unit comprising: a support frame; an intake duct supportedby the support frame for coupling to an intake end of the gas turbineengine; an exhaust duct supported by the support frame for coupling toan exhaust end of the gas turbine engine; an engine-side connectorstructurally attached to the support frame and connected for datacommunication with test equipment associated with the operation andtesting of the engine, the engine side-connector having a connectinginterface including both data connectors and structural connectorsconfigured to be interfaced all at once in a single operation withcorresponding data connectors and structural connectors of a test cellstructure.
 10. A pre-dressing unit according to claim 9, wherein thesupport frame comprises a rail on which at least one of the intake ductand the exhaust duct is movably supported.
 11. A pre-dressing unitaccording to claim 9, wherein the test equipment are selected from thegroup consisting of: a starter motor, an engine oil pressure regulator,a pressure sensor, a temperature sensor, a fuel supply line and an oilsupply line.
 12. A pre-dressing unit according to claim 9, wherein thesupport frame is removably mounted to a mobile base.
 13. A pre-dressingunit according to claim 9, wherein the support frame comprises an enginemount provided on a side of said engine-side connector opposite to saidconnecting interface.
 14. A connector assembly for a turbofan enginetesting facility, the connector assembly comprising: an engine-sideconnector structurally attached to the gas turbine engine, having afunctional interface comprising a plurality of engine-side connectionsfunctionally connected to equipment associated with the operation andtesting of the engine; and a mating test-side connector associated withthe testing facility comprising a plurality of corresponding test-sideconnections; the engine-side connector and the test-side connectorhaving cooperating guiding mechanism configured to structurallyco-operate and restricting relative motion between the engine-sideconnector and the test-side connector along an engagement axis whileestablishing alignment of the engine-side connections with the test-sideconnections as the engine-side connector and the test-side connector arebrought together for connection; and the engine-side connector and thetest-side connector having a cooperating locking mechanism to releasablylock the engine-side connector to the test-side connector along theengagement axis.
 15. A connector assembly according to claim 14, whereinthe guiding mechanism comprises a guiding member attached to one of theengine-side connector and test-side connector, and, a correspondingguiding passage disposed on the other one of the engine-side connectorand test-side connector for receiving the guiding member.
 16. Aconnector assembly according to claim 15, wherein the guiding membercomprises an outwardly tapered portion and the passage comprises acorresponding inwardly tapered portion.
 17. A connector assemblyaccording to claim 15, wherein the guiding passage comprises a roller.18. A connector assembly according to claim 14, wherein the lockingmechanism comprises a follower attached to one of the engine-sideconnector and test-side connector, and, a movable keeper attached to theother one of the engine-side connector and test-side connector; themovable keeper having a channel with an opening to receive the followerwithin the channel.
 19. A connector assembly according to claim 18,wherein the channel on the movable keeper has a tangential vector beingat an angle from the engagement axis to produce a camming action on thefollower that pulls the engine-side connector and the test-sideconnector together along the engagement axis upon forward motion of thekeeper.
 20. A connector assembly according to claim 18, wherein themovable keeper is actuated by a linear actuator.
 21. A connectorassembly according to claim 18, wherein the follower comprises a lughaving a roller at a distal end thereof.
 22. A pre-dressing unit for anaircraft turbofan engine testing, the pre-dressing unit comprising: asupport frame including an engine mount; an intake duct supported by thesupport frame and configured to mount to an intake end of the turbofanengine; an exhaust duct supported by the support frame and configured tomount to an exhaust end of the turbofan engine; an engine-side dataconnector mounted to the support frame and having a functional datainterface comprising a plurality of engine-side data connections; andequipment associated with the operation and testing of the engine, saidequipment including an engine oil pressure regulator carried by thesupport frame and functionally connected to a corresponding engine-sideconnection on the engine-side data connector for allowing adjustment ofoil pressure during engine testing operation without having to stop theengine.